;;; cl-synth : A software synthesiser for Common Lisp
;;; Copyright (C) 2010  Richard van Roy - (pluijzer [at] gmail [dot] com)

;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation, either version 3 of the License, or
;;; (at your option) any later version.

;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.

;;; You should have received a copy of the GNU General Public License
;;; along with this program.  If not, see <http://www.gnu.org/licenses/>

(in-package :cl-synth)

(defun straight (i)
  i)

(defun calc-freq (i freq &optional (samplerate 48000))
  (/ (* i pi 2 freq) samplerate))

(defun oscil (freq samples function iteration 
	       &optional
	       (samplerate 48000)
	       (displace 0))
  (loop for i from 0 to (1- samples) collect
       (funcall function 
		(funcall iteration (calc-freq (+ i displace) freq samplerate)))))

;;; TODO: Can be optimised by calculating nearest value from only
;;;       one rotation.
(defun oscil-seamless (freq samples function iteration previous
			&optional
			(samplerate 48000))
  (let ((displace 
	 (nearest (oscil freq samples function iteration samplerate)
		  (first (last previous)))))
    (oscil freq samples function iteration samplerate displace)))
			
			
